Last week, the U.S. stock market suffered the greatest sudden drop in its history, for reasons that nobody on Wall Street can seem to decipher. But of all the explanations being examined—a tech glitch, Greek debt worries and fraud have all been discussed--the most troubling is not being given sufficient attention.

Coming on the very day that Congress considered two key financial reforms, the timing of the "flash crash" raises concerns that Wall Street is resorting to extreme tactics in its efforts to intimidate politicians who want to rein in the capital markets casino. Thursday's market plunge could have been an act of financial terrorism. Wall Street has both the motive and the means: Goldman Sachs, which is currently under investigation for a very different kind of fraud, has the trading power to make just such a market crash occur, and has much to lose from financial reforms moving through Congress.

On Thursday afternoon, the Dow Jones Industrial Average plummeted 700 points in about 10 minutes. A few hours later, top Democratic negotiators reached a compromise with Sen. Bernie Sanders, I-Vermont, over a plan to audit the Federal Reserve's secret bailout operations. The Fed has pumped nearly $4.3 trillion in bailout funds into the banking system since the onset of the crisis, and we know almost nothing about that money. The "Audit The Fed" amendment would finally tell the public the full extent of Wall Street's bailout operations.